Why can’t SigPort be a free service?

SigPort will be an affordable but not-free service. This has several benefits. First, it covers the operating cost which is non-trivial (for example, the popular arXiv service has an annual operating cost of about $1M and has been exploring options for financial sustainability). Second, this is an inherent quality control mechanism to mitigate abuse (such abuse would otherwise be prevalent in no-cost options and would require a large amount of dedicated resources to handle). It will be costly to spam SigPort, and users are encouraged to upload the best of their work. Certainly, the fee structure would need to be properly set to balance the benefit and attractiveness to the community so that there can be many users utilizing the system.